"export TERM=5250" or "set TERM 5250" (or "set TERM=5250"?) depending on
your shell. This tells tn5250 and/or terminfo/termcap to interpret the
"F100" string defined in the us5250 map as a backtab.
To get left control mapped to reset, change the following in us5250.map:
keycode 29 = Control
keycode 29 = Control_r
keycode 97 = Control
keycode 97 = Return